Generally, a motor of which the rotor is positioned on an outer side of a stator is called “outer rotor type motor”, while a motor with its rotor positioned on an inner side of a stator is called “inner rotor type motor”. The present invention relates to a stator assembly for outer rotor type DD (Direct Driving) motor used for washing machines, or for inner rotor type motor mainly used for air conditioners.
FIG. 1 is an exploded perspective of a conventional stator assembly, and FIG. 2 is a perspective showing a hole sensor portion and a power lead portion coupled to a conventional stator assembly.
Referring to FIG. 1, the conventional stator assembly has a structure that an insulator 150 is coupled to both the top and bottom portions of a stator core 10. The stator core 10 includes a circular base 15, a plurality of teeth 11 radially formed along the circumference of the base 15, and slots 12 providing a space between the adjacent teeth 11. The insulator 150 includes a coupling bushing 151 formed on its inner side; a teeth insulating portion 152 surrounding the teeth 11 and supposed to be coil-wound; and a groove 153 formed to be coupled to the ends of the teeth 11. FIG. 1 shows an outer rotor type stator assembly, which is similar to an inner rotor type stator assembly excepting that the inner rotor type stator core includes teeth formed inwardly on an inner side of its base and has no coupling bushing.
Referring to FIG. 2, to the insulator 150 of the conventional stator assembly are coupled a hole sensor portion 160 for sensing magnetic flux, and a power lead portion 170 for providing an electrical connection to a power source. The stator assembly is designed to have the hole sensor portion 160 coupled to the insulator 150.
In the conventional stator assembly, the teeth insulating portion 152 of the insulator 150 is coupled to the teeth 11 of the stator core 10, and a coil 200 is wound around the teeth insulating portion 152. The teeth insulating portion 152 is formed integrally with the insulator 150 from a resin material through ejection molding. The thickness of the teeth insulating portion 152 is accordingly greater than that of the teeth 11, and slot 154 are smaller than the slots 12 of the stator core 10. This makes a difference in physical characteristics, such as a change in the magnetic flux through a constant number of windings, and adversely leads to an increase in the amount of resin consumption for ejection molding. When needed to selectively form the coupling bushing 151 and a hole sensor coupling portion 155 on the insulator 150 as shown in FIG. 2, the process requires an increase in the amount of resin consumption for ejection molding increases as well as more complicated molds, thus raising the material cost.
Moreover, as the hole sensor coupling portion 155 is formed in a single position of the insulator 150, there is a limitation in the position to fix the hole sensor that the hole sensor portion 160 can be coupled only to a single defined position.
To overcome the above-mentioned problems, the inventors of the present invention propose a stator assembly of a novel structure.